Cinematographic dye printing



Dec. 28, 1948. -y l G. F. RAcKET'r I CINEMATOGRAPHIG DYE PRINTING mea Aug. s1, 194s fgaZdZ/whfz Patented Dec. 28, 1948 2,451,319 CINEMATOGRAPHIC DYE PRINTING Gerald F. Rackett, Los Angeles; Calif., assignorto vTechnicolor Motion Picture Corporation, Holly-k wood, Calif., a corporation of Maine v Application August 31, 1945, Serial No. ,613,828

s claims. (c1. zii-2.1)

V'Inprintingx motion pictures by imbibitiomfrom` a dye impregnated matrix to a dye-absorptive blank, it is customary to employ afrelief ,matrix linvwhich the gelatincoating is thicker 4in the shadows than in the highlights and a blank comprising a layerofgelatinor. other dye-absorptive material. In order. toobtain gooddenition in -the picture printedonthe blank it is necessary to-employ relativelyl hard gelatin and in order to :maintain intimate contact between thel matrix and blank while the dye is being imbibed by the :blank from the matrix, it is desirable to` soften thefgelatin .on the blank temporarily. AThis is .usually accomplished by passing 4the blank ing for optimum definition is somewhat above the point where edgetrouble begins. 'I-Ieretofore it lhasbeennecessary tor tolerate imperfect -definivtionor encounter some edge trouble, and as ay practical matter it has'beencustomary to promise" between the two evils. 1 l

The aforesaid edge trouble results from `the fact that the valleys ofthe relief matrixl do not make good contact with the blank Aalongthe edges `of the pictures during the transferlprocess, as

'they wo uld if the blank were swollen Awith water -to agreater degree. This lack ofA intimate contact interferes with the transfer of dye, resulting .in imperfect printing alQng the margin of the, picture. Ordinarily this edge trouble is-conflned to anarrowzone just inside the sprocket holes. In the case of iilm having a sound-track inside one row of sprocket` holes the edge trouble is usually confined to the edges of the pictures along "the other row of sprocket holes; en the sound-- .track side the edges of the pictures `are too remote from the sprocketholes to -bexsubject to the trouble.

vObjects ofthe present invention arefto avoid 1 vtheaforesaid edge trouble and to afford intimate Acontact between the two iilms throughout/their Ventire width, to counteract 4the tendencyfor the .films tol separate at the edges, to permit the dye- 'absorptive layer of the blank film to be yhardened to thefoptimum degree, to avoid the `necessity-of softening this layer excessively in order to maintain intimate contact, and generally to improve the art of printing pictures by. dye transfer,

, the? with dyes, ,which Soak. intoiheblank. r

UNITED STATES PATENT DFHCE 2 dyes which are deposited on the surfaceof the blank. f

' According to the present invention the apparatus comprises an endless belt adapted to travel in an orbital path, the belt having marginal roWs of teeth shaped to t into the sprocket holes of superposed films to hold the films in registry while the iilms are traveling with thefbelt, and the belt being curved transversely so that it is concave on the film side, whereby the margins of the iilms, when pressed tightly against the belt, remain in intimate contact while on the belt.y The belt is trained over sheaves'with relatively straight portions extending from sheave to sheave and the lms-arefed to the belt where the belt is relatively straight, preferably in the same one of the aforesaid straight portions. The films travel with the `belt throughout a `portion of its orbit andare then conducted away from the belt, preferablyin the same straight portion in which they are fed to the belt at a location in advance of the location where they are applied to the belt. In the preferred embodiment the belt is rendered concave on the film side by opposed rollers on opposite sides of the belts at a location intermediate the aforesaid locations, where. there is no film onthe v belt.

For the purpose of illustration a typical ,embodiment of the invention is shown in the accompanyying drawing in which Fig. 1 is adiagram of imbibition apparatus for printing a blank film from a matrix film;

Fig. 2 is a section on line 2--2 of Fig. 1;

Fig. 3.is a side view of the mechanism shown in Fig. 2; and f Fig. 4 is a section on line 44 of Fig. 1.

The particular embodiment chosen for the purpose of `illustration comprises a pin belt I trained over sheaves 2 and 3f, the belt having marginal rows ofteeth or pins 4 adapted to iit into the sprocket holes of the blank and matrixfilms 6 and 1 while the two films travel in superposition on the belt. The blank (i feeds from a supply reel 8 throughan elevator comprising upper rolls 9 rotating about iixed axes and lower rolls II which are supported by the lm loops and which .move up and down to accommodate variations in thev degree of nlm shrinkage and differences in the ,rate of drive of the belt I and the driven sprocket wheels. From the elevator the blank passes through a pre-wet tank I2 and thence to a roll tank I3 where the blank is seatedon the belt by means of a roller I4.

The matrix 1 feeds from a supply reel I6 over -a fir i\ r e n sprocket wheel yI1tl1ence through Van 5 opposite sides of the belt for bending the belt transversely so that it is concave on the lm side, whereby the margins of the films are held in intimate contact While on the belt.

6. In the art of printing by imbibition from a dyed matrix to a blank having a dye absorptive layer, apparatus comprising a plurality of sheaves, an endless belt trained over the sheaves to travel in an orbital path with relatively straight portions extending from sheave to sheave, means in one of said straight portions for feeding a plurality of films into superposition on the belt, the belt having marginal rows of teeth shaped to t into the sprocket holes of superposed films to hold the films in registry while the lms are traveling with the belt and, in advance of said means in the same straight portion, opposed rollers on opposite sides of the belt for bending the belt transversely so that it is concave on the lm side, whereby the margins of the films are `neld in intimate contact while on the belt,

7. In the art of printing by imbibition from a dyed matrix to a blank having a dye absorptive layer, apparatus comprising a plurality of sheaves, an endless belt trained over the sheaves to travel in an orbital path with relatively straight portions extending from sheave to sheave, means in one of said straight portions for feeding a plurality of films into superposition on the belt, the belt having marginal rows of teeth shaped to fit into the sprocket holes of superposed films to hold the films in 'registry while the lms are traveling with the belt, means in advance of said means in the same straight portion for feeding the films from the belt and, intermediate said means in the same straight portion, means for bending the belt transversely so that it is concave on the lm side, whereby the margins of the lms are held in intimate contact while on the belt.

8. In the art of printing by imbibition from a dyed matrix to a blank having a dye absorptive layer, apparatus comprising a plurality of sheaves, an endless belt trained over the sheaves to travel in an orbital path with relatively straight portions extending from sheave to sheave, means in one of said straight portions for feeding a plurality of lms into superposition on the belt, the belt having marginal rows of teeth shaped to t into the sprocket holes of superposed films to hold the films in registry while the lms are traveling with the belt, means in advance of said means in the same straight portion for feeding the lms from the belt and, intermediate said means in the same straight portion, opposed rollers on opposite sides of the belt for bending the belt transversely so that it is concave on the film side, whereby the margins of the lms are held in intimate contact while on the belt.

GERALD F. RACKETT.

REFERENCES CITED The following references are of record in the nl@ of this patent:

UNrrED STATES PA'I'ENTS Number Name Date 1,638,561) Beveridge Aug. 9, 1927 1,707,699 Whitney Apr. 2, 1929 

